Apparatus for contour boring elongated sleeves of small internal diameter



A ril 21, 1964 E. E. JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER 9 Sheets-Sheet 1 Filed Feb. 9. 1961 {.INVENTOR. M BY April 21, 1964 E. E. JENNINGS APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER 9 Sheets-Sheet 2 Filed Feb. 9, 1961 INVENTOR.

ATTORNEK April 21, 1964 E. E. JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER 9 Sheets-Sheets Filed Feb. 9. 1961 INVENTOR.

- April 21,1964 E E. JENNINGS 3,129,445

APPARATUS FOE CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9. 1961 9 Sheets-Sheet 4 INVENTOR.

April 21, 1964 E. E. JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9. 1961 9 Sheets-Sheet 5 gINVENTOR. W

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April 21, 1964 E. E. JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9. 1961 9 Sheets-Sheet 6 INVENTQR.

, 4 gm 8- z 15' 4-6 BY April 21, 1964 5, JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9. 1961 9 Sheets-Sheet 7 INVENTQR.

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April 21, 1964 E. E. JENNINGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9. 1961 9 Sheets-Sheet 8 INVENTQR.

Aprll 21, 1964 JENN|NGS 3,129,445

APPARATUS FOR CONTOUR BORING ELONGATED SLEEVES OF SMALL INTERNAL DIAMETER Filed Feb. 9, 1961 9 Sheets-Sheet 9 4) 20 9 4 v///// F\ f IN V EN TOR.

United States Patent Ofifice 3,129,445 Patented Apr. 21, 1964 APPARATUS FOR (IQNTGUR EGRBJG ELUN- GATED SLEEVES (BF SMALL INTERNAL DIAMETER Edward E. Jennings, Cleveland, Ghio, assignor to The Pipe Machinery Company, Wickliiie, Ohio, :1 corporation of Ohio Filed Feb. 9, 1961, er. No. 88,167 5 Claims. (Cl. -129) This invention relates to high speed contour cutting of internal surfaces, including tapered threads in metal articles, and particularly to an apparatus for high speed boring of contoured bores and tapping of tapered threads in pipe sleeves and the like by a single pass or mutiple passes.

For the purposes of illustration, the invention is described herein as applied to the tapered tapping of elongated pipe-connecting sleeves of small internal diameter, its application to other threading and contour boring operations being apparent from the illustrative example.

Heretofore, in the taper tapping of pipe-connecting sleeves, a common practice has been to use a cutting head or carrier which is insertable in the sleeve in coaxial relation therewith and which is provided with a plurality of circumferentially spaced chasers arranged to slide radially of the head and concurrently cut the sleeve. Generally, the chasers are engaged by wedges or other operating means in the head and thereby caused to advance and recede radially in timed relation to the relative axial travel of the sleeve and head.

A second practice is that commonly employed is conventional automatic lathes and threading and boring machines wherein a single cutter is supported on a nonrotatable tool arm so as to be inserted into a sleeve. The sleeve is carried in a rotatable chuck and the arm is mounted on the cross slide of the lathe or machine so that it can be advanced and receded transversely of the axis of the sleeve while advanced endwise of the sleeve, and thus perform tapered tapping. In this operation, the thread or contoured bore may be produced by successive light slow speed cutting passes of the tool along the sleeve, or by faster and heavier cuts of carbide tools.

In some instances, for non-tapered threading, a tool arrn carrying a single cutting point is used, the arm being carried by the rotatable head of the lathe, and the workpiece being held in a non-rotatable stationary chuck. This latter arrangement usually requires Successive light passes of the point.

The first of these prior structures is unsatisfactory because the carrier and tool arm cannot be made sufiiciently rigid and heavy to prevent deflection and chatter. A plurality of chasers are required and each must slide relative to the head while resisting the heavy torques imposed by the cutting operation. At the same time, they must fit precisely in the carrier and maintain the fit under varying heating effects produced by the cutting operations. They must themselves be relatively rigid as also must the wedges or operating means and the carrier itself. These parts require a certain irreducible minimum of space. At the same time, they require enough metal to conduct away substantial amounts of heat when used for high speed cutting. The amount of metal necessary to afford rigidity, precision, and heat conduction for a tool arm for high speed deep cuts without binding is too great to be accommodated in sleeves of small inter nal diameter, for example from one and one-half to three inches in internal diameter, employing an arm long enough for threading such sleeves for the normal distance endwise of at least two inches, and as much as four and onehalf inches, from each end toward their axial mid-portion.

On the other hand, the practice of rotating the sleeve, as in automatic screw machines, is not adapted to rapid production of heavy parts at high speed. Further, it has the disadvantage of requiring precise chucking of the work pieces in rotatable chucks.

The prior structures employing a single rotatable tool arm more nearly approach the present invention, but, again, are not adapted for forming tapered threads in small diameter sleeves of from an inch and one-half to three inches in internal diameter. The tool arm is not suificiently rigidly supported so that the tool tip can cut a highly finished surface or thread with dimensional precision from the blank metal at high speed and with deep cuts.

The principal object of the present invention is to provide an apparatus for the high speed internal contour cutting, such as internal boring and tapered tapping, of elongated sleeves of small internal diameter with a single tool arm which supports the tool tip, or tips, and which is rotatably driven while in cutting relation to a non-rotatably supported sleeve.

A more specific object is to provide a tool carriage having an elongated rigid tool arm which is supported with a high degree of rigidity while rotated about the axis of the sleeve and advanced or receded relative to the sleeve axis while the sleeve is constrained from rotation, and which arm supports a cutting tip or tips in fixed relation to the arm and in variable eccentric relation to the sleeve. For very small diameter sleeves, the tool arm substantially fills the sleeve or bore being cut, allowing just enough radial clearance to permit removal of chips from between the bore wall and arm and to move the tool radially out of cutting engagement at the completion of the cutting operation.

Another specific object is to provide a single rotatable tool carrier for effecting the above contour boring and tapping of sleeves of an internal diameter as low as one and one-half inches with lengths from the normal length of two inches up to sleeves of three inches in internal diameter and as long as eight inches.

Another object is to control accurately the advance and recession of the tool carrier at all times during the cutting operation.

Various objects and advantages of the present invention will become apparent from the following description wherein reference is made to the drawings, in which:

FIG. 1 is a side elevation of a machine embodying the principles of the present invention;

FIG. 2 is a left end elevation of the machine illustrated in FIG. 1;

FIGS. 3A and 3B are the left and right end vertical longitudinal sectional views through the spindle axis of the machine and are taken on the line 33 of FIG. 2;

PEG. 4 is an enlarged plan view of a portion of the mechanism employed for causing relative approach of the spindle and chuck;

FIG. 5 is a similarly enlarged vertical sectional view taken on the line 55 of FIG. 4 and showing the sine bar mechanism and portions of the control therefor;

FIG. 6 is a front elevational view of a cutter mechanism housing structure;

FIG. 7 is a vertical sectional view taken on the line 7-7 of FIG. 6;

FIG. 8 is a horizontal sectional View taken on the line 8-8 in FIG. 6, and showing the antifriction mounting of the tool carrier;

FIG. 9 is a fragmentary sectional view taken on the line 9-9 of FIG. 6;

FIGS. 10 and 11 are a fragmentary top plan view and left end elevation, respectively, of part of the sine bar control mechanism embodied in the present invention;

FIG. 12 is a side elevation of the cutter mechanism housing structure detached from the machine;

FIG. 13 is a fragmentary vertical sectional view taken on the line 13-13 of FIG. 12;

FIG. 14 is an enlarged sectional view of the spindle drive mechanism, taken on the line 1414 of FIG. 12;

FIG. 15 is an enlarged sectional view of the clutch mechanism and is taken on the line 1515 of FIG. 2;

FIG. 16 is a fragmentary side elevation of a modified arrangement of tools on the tool supporting arm of the present invention; and

FIG. 17 is a right end elevation of the arm illustrated in FIG. 16.

Referring to the drawings, a machine for forming external threads on pipe and embodying the present invention, is shown for illustration, and comprises a frame or bed 1 on which is mounted a work-holding chuck 2 which is adapted to grip a length of pipe, or a pipe sleeve S, fed to it by a transfer mechanism and to hold the pipe in fixed axial position relative to the chuck with one end projecting toward the spindle of the machine for purposes of threading.

Mounted on suitable slideways 3 on the bed 1 is a spindle carriage 4 in which is rotatably mounted a spindle assembly, indicated generally at 5. The carriage 4, and the operating mechanism carried thereby, are mounted on the slideways 3 so that the carriage 4 can be reciprocated along the frame 1. Thus, the spindle and the work-holding chuck 2 can be moved relatively toward and away from each other axially of the sleeve S.

As more fully described in United States Patent No. 2,679,057, issued May 25, 1954, to Neil T. Sawdey, it is desirable that the spindle carriage be arranged for a rapid traverse axially from a starting position to the position in which the threading operation is to be initiated.

For this purpose, there is secured to the frame 1 of the machine a suitable hydraulic piston and cylinder assemblage 6 comprising a cylinder 7 and a piston 8 having a piston rod 9 which is connected to a slide 19. The slide 10 is reciprocable forwardly and rearwardly along suitable guideways on the bed 1. The slide 10 carries a suitable pin 11, with a follower 12 thereon, the follower 12 being slidable in a suitable slideway or groove 13 in a sine bar 14.

Prior to the initiation of the threading operation by the feed of the spindle carriage axially of the spindle, the sine bar 14 is held stationary in an advanced position. Consequently, upon the introduction of fluid into the head end of the cylinder 7, the slide 10 is moved in the direction in which the spindle carriage 4 is to be advanced. So long as the sine bar 14 is held in fixed position relative to the spindle carriage, the connection between the piston rod 9 and the carriage 4 of the spindle is a direct connection and the spindle carriage 4 and rod 9 move as a unit endwise of the spindle.

The rapid traverse and direct drive of the spindle carriage 4 by the assemblage 6 is stopped by a suitable means, preferably by the piston 8 reaching the rod end of the cylinder. When held in this position, the slide It} is held rigidly and firmly in its forwardmost position and, in this position, the feeding of the spindle carriage for the threading operation is begun.

For this purpose, the slot 13 of the sine bar 14 is on a bias to the direction of sliding of the sine bar and, consequently, as the sine bar 14 is slid transversely of the direction of movement of the slide it), it advances or retracts the spindle carriage 4, depending upon its direction of movement. Preferably, this is done in timed relation to the rotation of the spindle, as will now be described.

The spindle, indicated generally at 15, is provided with a main driving gear 16 which is driven by a suitable power driven worm gear 17. The worm gear is mounted 4 on a shaft 18 which is driven by a suitable gear 19 which, in turn, is driven through suitable means by a motor M carried on the carriage 4.

Connected to the shaft 13, through suitable speed reduction gears Ed, 21, 22, and 23, is a worm gear 24, as illustrated in FIGS. 11 through 14. This worm gear 24 drives a cooperating gear 25 which is rotatable with a clutch element 25a. A complementary clutch element 25b is rotatable with and slidable axially on the shaft 26 and is arranged to be slid axially thereof by a suitable piston and cylinder assemblage 28 so as to couple the gear 25 drivingly to the shaft 26. The shaft 26, in turn, drives a suitable pinion 2h which engages a rack. 3% carried on the sine bar 14.

As is apparent, the sine bar extends transversely of the machine and the rack extends parallel to the direction of travel of the sine bar. Accordingly, with the spindle operating and the clutch elements 25:: and 25b engaged, the shaft 26 is driven in a predetermined timed relation to the rotation of the spindle and, in turn, drives the sine bar through the pinion 29, and the rack 30 on the side bar, so that the sine bar 14 moves at a predetermined lineal rate of speed relative to the rotary speed of the spindle. This cooperation effects the advance of the spindle carriage by the sine bar 14 and thereby effects the advance of the spindle in relation to the rotation of the spindle, thus determining the pitch of threads.

As illustrated in FIG. 5, the sine bar 14 is yieldably urged in a direction away from that in which it is driven by the rack and pinion so as to eliminate, as near as may be, any slack in the drive. For this purpose, the sine bar is provided with a cylinder 32 in which is reciprocable a piston head 33 having a rod 34. The cylinder, in the form illustrated, is connected to the sine bar 14 and the rod 34 of the piston is connected to the carriage 4 of the machine. The structure is arranged so that pressure fluid can be admitted to one end of the cylinder to resist yieldably the movement of the sine bar 14 in the direction in which driven by the rack 30 and pinion 29 for advancing the spindle carriage 4.

A suitable check valve 35 is provided, this valve being set at a predetermined release pressure so that the maximum pressure resisting movement of the sine bar 14 by its rack 30 and pinion 29 can be predetermined. By admitting pressure fluid to the opposite side of the piston, the sine bar can be retracted at the end of the advance movement of the carriage of the spindle. The machine thus far described is known in the art.

To embody the present invention, the spindle carries a cutter head, indicated generally at 36, in which is mounted a cutting tool carriage 37. The carriage 37 preferably is in the form of a heavy frusto-conical metal body 33 having, adjacent its outer and larger base, a radially extending flange 39. The carriage 37 is antifrictionally supported in the head 36 for limited movement in opposite directions transversely or diametrally of the axis of rotation of the head.

For this purpose, preloaded anti-friction means are provided. The anti-friction means may comprise two sets of anti-friction rollers 4ft. The rollers of one set are interposed between the rear face of the flange 39 and a complementary forward bearing face 36a of the head. An annulus 41 is fixedly secured to the head 36 and has a rearwardly facing complementary bearing face 41a. The rollers 40 of the other set are interposed between the forward face of the flange 39 and the face 41a.

The rollers of each set are preferably caged in retainers 42 and are disposed with their axes in planes normal to the axis of the head. The axes of the rollers are parallel to each other and extend transversely of the path of oscillation or reciprocation of the carriage 37. The preloading of the hearings or rollers assures that the carriage 37 moves at all times with its axis parallel to the axis of the rotation of the head. This preloading is necessary for high precision work.

The carriage 37 is constrained to move in opposite directions along one diameter only of the head 36 while maintained in a fixed circumferential position relative to the head. The flange 39 is provided with a plurality of elongated slots 43 which are elongated in the direction of the diametral movement of the carriage. Spacers 44 are disposed in the slots and secured by suitable bolts to the clamping annulus 41 and the head 36.

For effecting the diametral movement of the carriage 37, a block 45 is mounted in the head 36 for guided radial sliding movement parallel to said diametral path of movement of the head 36.

The block 45 is securely fastened, as by bolts, to the flange 39 of the carriage 37 for movement diametrally with the carriage. Diametrally opposite the block 45 is a guide block 46 which is mounted in the head 36 for movement parallel to the block 45. The block 45 is arranged to be driven inwardly and outwardly relative to the axis of rotation in relation to the movement of the spindle 15 and head 36 relatively toward and away from the chuck 2. For driving the block 45, it is provided with a spline 47. The block 45 is connected to a cam block 48 by inter-engagement of the spline 47 in a complementary cam groove 49 in the cam block. The cam block 48 is mounted in the head 36 for guided sliding movement, parallel to the axis of the spindle, in opposite directions, selectively, and by so doing, recedes and advances the block 45.

As best illustrated in FIG. 6, the block 45 is provided with a pin 50 which is engageable with a plunger 51. A spring 52 resists movement of the plunger in a direction toward the axis of rotation of the head 36. Thus, as the cam block 48 is moved rearwardly to the spindle head 36, the block 4-5 recedes from the axis of rotation.

For supporting the tool in the carriage 37, the carriage is provided with a tool arm 53 which is coaxial with, and extends forwardly from, and forms a portion of, the carriage. The arm 53 carries a single high speed cutting tool 54 adapted to make a finished cut at high speed in a single pass over the blank stock. In the form illustrated, the tool is a carbide, or equivalent, high speed, multitooth thread chaser. Such tools complete a cut, leaving a finished surface, in a single pass, but to do so they must take a relatively deep and positive cut and be rigidly supported free from any vibration and chatter.

Accordingly, the arm 53 is made as large in diameter as possible in relation to the minimum internal diameter of the smaller sleeve to be tapped so that the arm substantially fills the sleeve with only sufficient allowance for chip removal and for retracting the tool from the finished surface of the sleeve upon completion of the tapping, or contour cutting, operation.

Also, for enhancing rigidity While reducing flie dangers of brittleness, the arm preferably is carbide, or a carbide casing and steel core.

In the form illustrated, the tool 54 is positioned circumferentially of the arm 53 so that it recedes from the workpiece and approaches the axis of rotation as the cam block 48 is moved rearwardly relative to the head 36.

Thus, upon taper tapping a sleeve S in FIG. 3B, as the head 36 is advanced axially of the sleeve, the cam block 48 is moved rearwardly relative to the head 36, thus retracting the block 45 from the workpiece toward axis of rotation. The carriage 37 and tool 54 are eccentric to the axis and at the opposite side thereof from the block 45 in the starting position. Hence, the tool 54 approaches the axis as it advances endwise of the sleeve and taps the sleeve with a thread which tapers inwardly from the end toward the longitudinal mid-portion of the sleeve.

In order to advance and retract the cam block 48, a suitable power transmitting means in the form of a cylindrical sleeve member 55 with a radial flange 55a is connected to the cam block 48 by means of a coupler 55b. The member 55 is coaxial with, and disposed within the spindle, except for the block connecting portion of the flange 55a, and is slidably mounted therein for axial reciprocation. The member 55 is normally urged in a direction rearwardly away from the forward face of the spindle by means of springs 56. Thus, it is continuously urged by the spring in a direction for causing the block 45 to recede from the axis of rotation of the head 36. The structure thus far described for advancing and receding the block 45 is broadly that disclosed in U.S. Patent No. 2,679,057, issued May 25, 1954, to Neil T. Sawdey. A tubular sleeve 57 is mounted in the spindle in coaxial relation to the member 55 and is rotatably supported at one end in coaxial relation by means of suitable ball bearings 57a. The bearings 57a also connect the member 55 and sleeve 57 for movement together axially of the spindle during relative rotation of the member 55 and the sleeve 57.

The sleeve 57, in turn, is fixedly connected to a suitable piston 58 which is reciprocable axially in a cylinder 59. The cylinder 59, in turn, is movable axially of the spindle by means of a follower 60 which is movable endwise of the spindle. The follower 60 cooperates with a sine bar 61 which is slidable laterally of the spindle. Fluid pressure can be admitted to either end of the cylinder 59 and the other end vented.

The initiation of the movement of the block 45 toward and away from the axis is controlled in relation to the position of the spindle head along the slideway 3 and, hence, in relation to its position axially relative to the chuck 2. For controlling the advance and recession of the block 45 by the member 55, a suitable hollow rod 65 is provided and extends into, and is slidable axially of, the piston 58. The rod 65 protrudes rearwardly from the piston and extends beyond the rear of the spindle. At a location beginning a short distance from the rear of the spindle housing, the rod 65 is provided with a detachable sleeve rack 68 which is secured in fixed relation on the rod 65 by means of a nut 69. The rack 68 is engaged with a suitable pinion 70 which is mounted for rotation about an upright shaft 71 on the spindle carriage. For this purpose, the pinion 70 is provided on one end of a sleeve 72, the upper end of which carries a pinion '73 which engages a rack 74 on the sine bar 61. Thus, the movement of the sine bar 61 in opposite directions is dependent upon the movement of the rack 68 and, therefore, of the rod 65 forwardly and rearwardly parallel to the axis of the spindle. The sine bar 61 is connected to the rod 75 of a suitable piston 76 operable in a cylinder 77 to which pressure may be admitted at either end for advancing and retracting the sine bar.

Generally, the piston and cylinder arrangement is such that the piston opposes movement of the sine bar in a direction for retracting the chasers from the work by the springs 56. In order to maintain a predetermined pressure in the head end of the cylinder 77 to resist the movement of the sine bar yieldably against the driving force of the rack 68 and pinion 73, the pressure fluid is supplied to the head end of the cylinder '77 by means of a suitable pump 83 driven by a motor 81. Interposed between the head end of the pump and the cylinder is a check valve 82 which permits the flow to the head end of the cylinder but prevents the return therefrom. Connected in a by-pass circuit around the check valve is an adjustable relief valve 83. Thus, pressure fluid, supplied by the pump to the head end of the cylinder 77, is ample to return the sine bar 61 to the starting position when such is permitted by the proper movement of the rack 68 and rod 65. However, when the sine bar 61 is being moved in the opposite direction, during the cutting operation, for receding the cutting tool, the pressure in the head end of the cylinder must discharge through the relief valve 83 which, being set for a predetermined pressure, maintains a yieldable and substantially constant resisting force against the travel of the sine bar in the direction for receding the chasers.

The portion of the rod 65 which extends to the rear of the spindle is slidable through a pasage in a suitable stop 85 which is mounted in fixed position on the frame 1 of the machine and hence does not move endwise of the frame with the spindle. At the end of the rod beyond the stop 85 in a direction away from the spindle, the rod is threaded and provided with two adjustable stop nuts 86 and 37. These nuts engage the rear face of the stop 85 when the spindle is moved forwardly on the slide 3 a predetermined distance. Upon their engagement with the stop 85, the movement of the rod 65 forwardly with the spindle is arrested and the spindle continues to advance. This causes a relative rearward movement of the rod 65 with respect to the spindle and drives the rack 68 and pinion gears 70 and 73 and hence the sine bar 61 for controlling the rate of retraction of the block 45 away from the axis and hence advancement of the tool toward the axis.

Continued movement of the spindle carriage toward the chuck thus drives the rod as to the left relative to the spindle carriage, thereby moving the rack to the left and causing it to rotate the pinions 7t} and '75 and thereby drive the rack 74 of the sine bar 61, thus urging the sine bar to the left against the resistance of the piston and cylinder assemblage 77. As the sine bar moves to the left, it imposes a movement, to the left, of the cylinder 59. Since the piston 58 is operable in the cylinder 59 and is urged to the right by the fluid pressure between the left end of the piston and the cylinder, the recession of the cylinder 59 permits the piston to recede to the left, always, however, while yieldably urged and held against the opposite end of the cylinder by fluid pressure. Thus, a yieldable connection is provided. The movement of the piston to the left draws with it the rod 57 which, through the medium of the bearings 57a and member 50, permits the flange 55a to retract from the spindle head 36. This retraction of the member 55), under the control of the sine bar 61, thus causes the block 45 to recede from the axis of the pipe and provide a taper cut.

At the end of the cutting operation, fluid pressure is admitted to the right of the piston 58, the cylinder being vented at its left end. The piston 58 moves to the left relative to the cylinder and further recedes the tool so that before return of the head the tool is clear of the sleeve and the sleeve can readily be removed axially.

Thus, the piston 58 and cylinder 59 provide an extensible and retractible means drivingly interconnecting the sine bar and pipe engaging device or rod 57. This extensible and retractible means, when held in extended or retracted position, causes the rod 57 and sine bar 61 to move in predetermined relation to each other, but it can be moved from retracted to extended condition and vice versa to cause the member to move independently of the movement of the sine bar.

Upon return of the spindle carriage, the efiect is a relative motion of the rod or pipe 65 in the advance direction of the spindle carriage, which, due to the pressure in the cylinder 77, restores the sine bar 61 to its starting position and returns the pipe or rod 65 and rack 68 to their starting position relative to the spindle carriage.

If it is desired to out only cylindrical bores and constant diameter threads, the stops 86 and 87 may be removed, or moved to inoperative positions and the sine bar 61 secured in fixed position. As a result, the tube 57 and hence the member 55 remain in fixed axial position relative to the spindle during rotation and advance of the spindle.

It is apparent from the foregoing description that the advance and recession of the tool relative to the rotational axis can be varied to meet different conditions by changing the grooves in the sine bar 61, or by changing the sleeve rack 68 and pinion gear 79, or both. For example, the slot in the sine bar 61 is shown as a lineal slot biased to the length of the bar endwise the path of travel of the sine bar 61. By making the slot in the form of acurve of constant or variable radii, different effects can be obtained for cutting tapered threads, or threads of two different diameters, successively, and for contour boring of the interior of the sleeve. In all instances, the cutting is maintained at high speed with the tool 54 making a single pass relative to the workpiece which removes the metal to the full depth from the original surface necessary for the shape desired, and which leaves the resulting formed surface in highly polished and finished condition and precisely dimensioned and shaped.

In many instances it is desirable to supply coolant to the tool and for this purpose a suitable pipe 89 is provided. This pipe extends entirely through the tubular sleeve 57 and the tubular rod 65. At the outer end of the rod 65, the pipe 89 is connected to a flexible hose 50 which, in turn, is connected to a source of coolant under pressure. The opposite end of the pipe 89 is connected by a slip fit connection, indicated at 91, to a flexible hose 92.

A plate 93 is provided on the inner end of the carrier 37 in sealed relation thereto and has a passage 94 which leads into a bore 95 in which the arm 53 is rigidly secured. The other, or forward, end of the hose 92 is connected to the plate 93 so as to discharge coolant from the pipe 89 into the bore 95. The arm 53 is provided with an axial duct 96 in communication at its inner end with the bore 95. Two transverse ducts 97 are provided in the outer end of the arm 53 and are in communcation with the duct 96. The ducts 95 are arranged for discharging coolant onto the tool or chaser 54.

The hose 92 is flexible so as to accommodate itself to the radial movement of the carrier 37. The slip fit connection 91 is arranged for relative rotation between the pipe 89 and the hose 92 and also for relative axial extension and retraction of the pipe and hose while maintaining a sealed joint therebetween. This axial movement is to permit the hose 92 to be connected to the plate 93 while the carrier 37 is removed from the spindle head.

Thus, in operation, the coolant can be supplied for cooling the tool and assisting in removing chips during the cutting operation.

In some instances it is desirable to perform cutting operations with two tools concurrently. In such an instance an arm 1% is employed. This arm is identical with the arm 53 except that it is arranged to carry two cutting tips 101 and 102, respectively. These tools or tips are spaced apart circumterentially of the arm about the axis of the arm and equidistantly from, and at opposite sides of, the diametral path of movement of the axis of the arm 100 relative to the head as the arm is moved radially of the rotational axis of the spindle by the carrier 37.

For example, assume that, in FIG. 17, the line x-x represents the diametral path of movement of the axis of the arm relative to the spindle head due to the movement of the carrier radially of the spindle axis. One of the tools 101 is on one side of the line xx and the other tool on the opposite side. The tools are spaced equidistantiy from the line xx, and preferably is 30 about the axis of the arm from the line x-x. Thus, upon the normal radial movement of the arm 1% by the carriage, the tools 101 and 162 are concurrently retracted properly from their cutting relation to the inner wall of the sleeve. Assuming that the direction of rotation of the spindle is as indicated by the arrow 103 in FIG. 17, then the tool 191 may be a rough cutting tool and the tool 152 the finish cutting tool.

The arm 100 is of such diameter relative to the interior wall of the sleeve that the heavy chips cut by the tool 101 can be removed readily from the 300 space between the tools. The 60 space between the tools is ample for removal of the lighter finishing chips cut by the tool 152.

In the claims, the words internally machining are used and this term is used in its broader sense to include contour boring, counterboring to different diameters, and tapered boring and threading.

Having thus described my invention, I claim:

1. An apparatus for internally machining elongated internal walls of bores of small diameter and comprising a rotatable power driven spindle head, a chuck to hold a workpiece having a bore with the bore coaxial with the spindle head, a carrier mounted on the head for guided movement in opposite directions relative to the head along a predetermined path which extends transversely of the axis of rotation, and is parallel to a plane normal to the axis of rotation, said carrier having a rigid body portion, a single elongated tool arm having one end rigid with, and in fixed relation to, the body portion, said arm extending outwardly beyond the carrier endwise of the axis of rotation, in a direction toward the chuck, cutting means mounted in fixed position on the outer end portion of the arm and extending laterally therefrom so that the cutting means can be supported by the arm rigidly in cutting relation to the bore wall, during relative axial movement of the chuck and spindle head toward each other, said cutting means being capable when so supported, during said relative advance axially of the sleeve, of making a spiral out along the bore at high speed, means for causing said relative axial movement of the chuck and spindle head, mechanical power transmitting means connected to the carrier and rendered operative in preselected relation to said relative axial movement to move the carrier along its said path in predetermined relation to the relative axial movement, said carrier having a radially extending flange portion with front and rear planar surface portions in planes normal to the axis of rotation, said head having front planar bearing face portions parallel to, facing toward, and spaced rearwardly from, the rear surface portions, retaining means on the head and having rear planar bearing face portions parallel to, facing toward, and spaced forwardly from, the front surface portions, anti-friction rolling elements interposed between said rear surface portions and said front face portions and between said front surface portions and said rear face portions, said elements being rotatable about axes which are parallel to each other and to said surface portions, and said axes extend transversely of said path of movement of the carrier relative to the head, and said elements, surface portions, and

face portions cooperating to support the carrier for antifriction movement along its said path relative to the head, said elements being spaced outwardly radially from the axis of rotation and so distributed about the axis of rotation at said front and rear surface portions that turning moments imposed on the carrier by reactionary forces on the tool acting through the arm about axes extending transversely of the axis of rotation are resisted by reactionary forces imposed in one direction on the rear surface portions at one side of the axis of rotation by said front face portions acting through some of the elements and by reactionary forces imposed in an opposite direction on the front surface portions at the opposite side of the axis of rotation by said rear face portions acting through some of the others of said elements.

2. The apparatus according to claim 1 wherein said anti-friction means are preloaded.

3. The structure according to claim 1 wherein the elements are rollers with axes parallel to each other.

4. The structure according to claim 1 wherein said elements are distributed about the axis of rotation in a pattern such that, with the axis of rotation as the origin of rectangular coordinates on a plane normal to said axis of rotation, each quadrant contains a plurality of said elements.

5. The structure according to claim 1 wherein the cutting means comprises two carbide chasers having their respective cutting edges spaced circumferentially of the axis of the arm from each other at opposite sides of a plane which extends through the axis of the arm and parallel to said path of the arm, and at equal acute angles, circumferentially of the axis, to said plane, said chasers being the only cutting means on the arm.

References Cited in the file of this patent UNITED STATES PATENTS 194,469 Schaub Aug. 21, 1877 414,357 Woodbridge Nov. 5, 1889 1,195,145 Mattingly Aug. 15, 1916 2,267,186 Blood Dec. 23, 1941 2,533,451 Guinsberg Dec. 12, 1950 2,627,194 Leifer Feb. 3, 1953 2,679,057 Sawdey May 25, 1954 2,954,570 Couch Oct. 4, 1960 2,979,993 Hedstrom Apr. '18, 1961 

1. AN APPARATUS FOR INTERNALLY MACHINING ELONGATED INTERNAL WALLS OF BORES OF SMALL DIAMETER AND COMPRISING A ROTATABLE POWER DRIVEN SPINDLE HEAD, A CHUCK TO HOLD A WORKPIECE HAVING A BORE WITH THE BORE COAXIAL WITH THE SPINDLE HEAD, A CARRIER MOUNTED ON THE HEAD FOR GUIDED MOVEMENT IN OPPOSITE DIRECTIONS RELATIVE TO THE HEAD ALONG A PREDETERMINED PATH WHICH EXTENDS TRANSVERSELY OF THE AXIS OF ROTATION, AND IS PARALLEL TO A PLANE NORMAL TO THE AXIS OF ROTATION, SAID CARRIER HAVING A RIGID BODY PORTION, A SINGLE ELONGATED TOOL ARM HAVING ONE END RIGID WITH, AND IN FIXED RELATION TO, THE BODY PORTION, SAID ARM EXTENDING OUTWARDLY BEYOND THE CARRIER ENDWISE OF THE AXIS OF ROTATION, IN A DIRECTION TOWARD THE CHUCK, CUTTING MEANS MOUNTED IN FIXED POSITION ON THE OUTER END PORTION OF THE ARM AND EXTENDING LATERALLY THEREFROM SO THAT THE CUTTING MEANS CAN BE SUPPORTED BY THE ARM RIGIDLY IN CUTTING RELATION TO THE BORE WALL, DURING RELATIVE AXIAL MOVEMENT OF THE CHUCK AND SPINDLE HEAD TOWARD EACH OTHER, SAID CUTTING MEANS BEING CAPABLE WHEN SO SUPPORTED, DURING SAID RELATIVE ADVANCE AXIALLY OF THE SLEEVE, OF MAKING A SPIRAL CUT ALONG THE BORE AT HIGH SPEED, MEANS FOR CAUSING SAID RELATIVE AXIAL MOVEMENT OF THE CHUCK AND SPINDLE HEAD, MECHANICAL POWER TRANSMITTING MEANS CONNECTED TO THE CARRIER AND RENDERED OPERATIVE IN PRESELECTED RELATION TO SAID RELATIVE AXIAL MOVEMENT TO MOVE THE CARRIER ALONG ITS SAID PATH IN PREDETERMINED RELATION TO THE RELATIVE AXIAL MOVEMENT, SAID CARRIER HAVING A RADIALLY EXTENDING FLANGE PORTION WITH FRONT AND REAR PLANAR SURFACE PORTIONS IN PLANES NORMAL TO THE AXIS OF ROTATION, SAID HEAD HAVING FRONT PLANAR BEARING FACE PORTIONS PARALLEL TO, FACING TOWARD, AND SPACED REARWARDLY FROM, THE REAR SURFACE PORTIONS, RETAINING MEANS ON THE HEAD AND HAVING REAR PLANAR BEARING FACE PORTIONS PARALLEL TO, FACING TOWARD, AND SPACED FORWARDLY FROM, THE FRONT SURFACE PORTIONS, ANTI-FRICTION ROLLING ELEMENTS INTERPOSED BETWEEN SAID REAR SURFACE PORTIONS AND SAID FRONT FACE PORTIONS AND BETWEEN SAID FRONT SURFACE PORTIONS AND SAID REAR FACE PORTIONS, SAID ELEMENTS BEING ROTATABLE ABOUT AXES WHICH ARE PARALLEL TO EACH OTHER AND TO SAID SURFACE PORTIONS, AND SAID AXES EXTEND TRANSVERSELY OF SAID PATH OF MOVEMENT OF THE CARRIER RELATIVE TO THE HEAD, AND SAID ELEMENTS, SURFACE PORTIONS, AND FACE PORTIONS COOPERATING TO SUPPORT THE CARRIER FOR ANTIFRICTION MOVEMENT ALONG ITS SAID PATH RELATIVE TO THE HEAD, SAID ELEMENTS BEING SPACED OUTWARDLY RADIALLY FROM THE AXIS OF ROTATION AND SO DISTRIBUTED ABOUT THE AXIS OF ROTATION AT SAID FRONT AND REAR SURFACE PORTIONS THAT TURNING MOMENTS IMPOSED ON THE CARRIER BY REACTIONARY FORCES ON THE TOOL ACTING THROUGH THE ARM ABOUT AXES EXTENDING TRANSVERSELY OF THE AXIS OF ROTATION ARE RESISTED BY REACTIONARY FORCES IMPOSED IN ONE DIRECTION ON THE REAR SURFACE PORTIONS AT ONE SIDE OF THE AXIS OF ROTATION BY SAID FRONT FACE PORTIONS ACTING THROUGH SOME OF THE ELEMENTS AND BY REACTIONARY FORCES IMPOSED IN AN OPPOSITE DIRECTION ON THE FRONT SURFACE PORTIONS AT THE OPPOSITE SIDE OF THE AXIS OF ROTATION BY SAID REAR FACE PORTIONS ACTING THROUGH SOME OF THE OTHERS OF SAID ELEMENTS. 